Neue Anforderungen an optimierende Energiesystemmodelle für die Kraftwerkseinsatz- und Zubauplanung bei begrenzten Netzkapazitäten

Recent changes in energy economic frameworks conditions lead to new requirements for energy systems models. Particularly in Germany, structural and locational changes in the power plant sector can be observed. Above all, this is due to the liberalisation process entailing the legal unbundling of system operators and generation companies as well as to the ambitious aims for the extension of wind energy. Consequently, modelling energy systems as single node systems, in which network constraints are neglected, can lead to suboptimal results. Most energy systems models offer the possibility to limit interregional energy exchange capacities. However, these so-called transhipment models normally neglect the actual load flows. Yet, there are several possibilities to adequately consider the characteristics of power transmission. In this paper, the most popular approaches, which are used in particular technical applications, such as the AC- (Alternating Current), the DC- (Direct Current) and the PTDF- (Power Transfer Distribution Factors) approach are introduced and discussed with respect to their application in energy systems models. In addition, first experiences with their implementations are presented.     

Economic capital for nonperforming loans

A portfolio of nonperforming loans requires economic capital. We present two models for forecasting the portfolio loss and its probability distribution. In the first model, the loss for each nonperforming loan entails a change in provision over the risk horizon. The risk determinants are the single-name concentration, measured by the Herfindahl–Hirschmann index, as well as a systematic factor and the idiosyncratic risk. Our second model allows for interportfolio diversification with a portfolio of performing loans because banks typically own both performing and nonperforming loans. In this model, the nonperforming loan is identified with its systematic risk. Both models allow for closed-form expressions of economic capital and for the capital charge of the single loan. We calibrate the macroeconomic model parameters statistically with a loss panel; the microeconomic parameters depend on the portfolio. The portfolio risk for nonperforming loans mainly depends on the volatility of the systematic economic factor. The dependence becomes more pronounced when interportfolio diversification is taken into account. The magnitude of interportfolio diversification is also marked. Finally, we calculate regulatory capital charges according to Basel II for past-due loans. The regulatory charges are on average smaller than our economic charges and, additionally, take the volatility of economic activity into account only implicitly.     

Beyond Profitability of Energy-Saving Measures—Attitudes Towards Energy Saving

Private homeowners can save considerable amounts of energy and money, if they retrofit their homes according to up-to-date energy efficiency standards. From an expert point of view, many of these technical measures are profitable in relatively short payback times, if only additional costs are considered. Apparently, many homeowners do not follow this type of rationality and do solely not regard their refurbishment as an investment. Drawing on the results of an empirical survey of retrofit activities among 1,008 homeowners in Germany, it is argued that refurbishments are the outcome of a broader decision which is shaped by an alliance of economic and non-economic motives and goals. Energy-saving measures is expected to lower the burden of operating costs in a perceptible way and secure the value of the house, but they must also correspond to needs like comfort, convenience or belonging in order to be realized.     

Economic policy strategies in major industrial countries

The stubborn weakness of growth in the industrial countries since the mid-seventies is a manifestation of a serious crisis of stabilisation and adjustment whose roots go far beyond the oil price increases. Against this background there was a marked turn in the direction of economic policy as a result of changes of government in 1979 in the United Kingdom and in 1981 in the USA and France. The programmes to stimulate economic growth were based on the supply-side concept in the UK and the USA but on the demand concept in France. Our article assesses the measures actually taken and the policy accent in the three countries against the background of previous economic developments and the prevailing political and institutional circumstances.